/**
 * Copyright (c) 2015-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

'use strict';

/* eslint-disable */
let chalk = require('chalk');
let execSync = require('child_process').execSync;
let spawn = require('cross-spawn');
let opn = require('opn');

// https://github.com/sindresorhus/opn#app
let OSX_CHROME = 'google chrome';

const Actions = Object.freeze({
    NONE: 0,
    BROWSER: 1,
    SCRIPT: 2
});

function getBrowserEnv() {
    // Attempt to honor this environment variable.
    // It is specific to the operating system.
    // See https://github.com/sindresorhus/opn#app for documentation.
    const value = process.env.BROWSER;
    let action;
    if (!value) {
        // Default.
        action = Actions.BROWSER;
    }
    else if (value.toLowerCase().endsWith('.js')) {
        action = Actions.SCRIPT;
    }
    else if (value.toLowerCase() === 'none') {
        action = Actions.NONE;
    }
    else {
        action = Actions.BROWSER;
    }
    return { action, value };
}

function executeNodeScript(scriptPath, url) {
    const extraArgs = process.argv.slice(2);
    const child = spawn('node', [scriptPath, ...extraArgs, url], {
        stdio: 'inherit'
    });
    child.on('close', code => {
        if (code !== 0) {
            console.log();
            console.log(
                chalk.red(
                    'The script specified as BROWSER environment variable failed.'
                )
            );
            console.log(chalk.cyan(scriptPath) + ' exited with code ' + code + '.');
            console.log();

        }
    });
    return true;
}

function startBrowserProcess(browser, url) {
    // If we're on OS X, the user hasn't specifically
    // requested a different browser, we can try opening
    // Chrome with AppleScript. This lets us reuse an
    // existing tab when possible instead of creating a new one.
    const shouldTryOpenChromeWithAppleScript
        = process.platform === 'darwin'
        && (typeof browser !== 'string' || browser === OSX_CHROME);

    if (shouldTryOpenChromeWithAppleScript) {
        try {
            // Try our best to reuse existing tab
            // on OS X Google Chrome with AppleScript
            execSync('ps cax | grep "Google Chrome"');
            execSync('osascript openChrome.applescript "' + encodeURI(url) + '"', {
                cwd: __dirname,
                stdio: 'ignore'
            });
            return true;
        }
        catch (err) {
            // Ignore errors.
        }
    }

    // Another special case: on OS X, check if BROWSER has been set to "open".
    // In this case, instead of passing `open` to `opn` (which won't work),
    // just ignore it (thus ensuring the intended behavior, i.e. opening the system browser):
    // https://github.com/facebook/create-react-app/pull/1690#issuecomment-283518768
    if (process.platform === 'darwin' && browser === 'open') {
        browser = undefined;
    }

    // Fallback to opn
    // (It will always open new tab)
    try {
        let options = { app: browser };
        opn(url, options).catch(() => {}); // Prevent `unhandledRejection` error.
        return true;
    }
    catch (err) {
        return false;
    }
}

/**
 * Reads the BROWSER evironment variable and decides what to do with it. Returns
 * true if it opened a browser or ran a node.js script, otherwise false.
 */
function openBrowser(url) {
    const { action, value } = getBrowserEnv();
    switch (action) {
        case Actions.NONE:
            // Special case: BROWSER="none" will prevent opening completely.
            return false;
        case Actions.SCRIPT:
            return executeNodeScript(value, url);
        case Actions.BROWSER:
            return startBrowserProcess(value, url);
        default:
            throw new Error('Not implemented.');
    }
}

module.exports = openBrowser;
/* eslint-enable */
